A traditional casting process for forming metal castings employs one of various types of molds for example, a green sand mold, a precision sand mold, or a steel die, having the exterior features of a desired casting, such as a cylinder head or engine block, formed on its interior surfaces. A core formed from sand and a suitable binder material and defining the interior features of the casting is placed within the mold or die. The sand core used to produce contours and interior features within the metal castings typically must be removed and reclaimed.
The mold or die is then filled with a molten metal or metal alloy. The casting is then removed from the mold or die and moved to a treatment furnace for heat-treating, removal of the sand cores, reclamation of the sand from the sand cores, and, at times, aging. Heat treating and aging are processes that condition the metal or metal alloy to achieve various desired resulting properties for a given application.
Once the casting is formed, several distinctly different steps generally must be carried out in order to heat treat the metal casting and reclaim the sand from the sand core. First, a portion of the sand core is separated from the casting using one or more techniques. For example, sand may be chiseled away from the casting or the casting may be physically shaken or vibrated to break-up the sand core and remove the sand. Additionally, where the molds include one or more orifices for accessing the cores, the orifices that are blocked must be cleared.
After or during the sand is removed from the casting, heat treating and aging of the casting generally are carried out in subsequent steps. The casting is typically heat treated if it is desirable to, among other treatments, strengthen or harden the casting or to relieve internal stresses in the casting.
Although many advances have been made in the metal casting industry, there remains a need for an improved process for removing the cores and residual sand from the casting.
Various objects, features, and advantages of the present invention will become apparent to those skilled in the art upon a review of the following detailed description when taken in conjunction with the accompanying drawings.